1. Field of the Invention
This invention relates to a mechanical anchorage device and to a method for connecting the device out in the field to the upstanding end of a rebar which may be embedded within and project from a section of concrete. The anchorage device forms a wide head on the rebar which will be covered with concrete to create one or more bearing surfaces and thereby enable the rebar to better withstand forces applied thereto through the concrete.
2. Background Art
Steel reinforcement bars (i.e., rebars) are well known to be embedded within a reinforced concrete structure (e.g., a wall, panel, or the like) so that the structure will be less likely to shift or suffer damage caused by physical forces, such as those generated during an earthquake. In some cases, the rebars can become prematurely separated from their concrete structure as a consequence of tensile loads applied to the rebar.
In order to stabilize and better hold the rebars in place within the concrete structure so as to more reliably withstand tensile loads, a relatively wide head is often formed to establish a wide bearing surface at the end of each rebar. The headed end is then covered over with additional concrete. However, it is sometimes difficult to form a wide head out in the field on a rebar that is already installed and embedded in a concrete structure with one end projecting from the structure to be subjected to a heading process. While it may be simpler to head the rebar prior to its installation in the field, the precise length of the rebar that will project from the concrete structure is often difficult to predict. That is to say, the end of the rebar may need to be cut and shortened in the field resulting in the preformed head being cut off the end. In other cases, the end of each rebar is bent over to form a hook so as to increase the bearing area thereof. Alternatively, a plate has been welded to the end of the rebar. In any case, special equipment and/or tools may have to be transported into the field for post-installation treatment of the top ends of the rebars to better resist tensile loads. The requirement for special equipment and tools slows the construction project and increases cost.
Accordingly, it would be desirable to be able to quickly and reliably connect a mechanical anchor to and increase the bearing surface at the upstanding end of a rebar that projects from a concrete structure out in the field without the cost or inconvenience of having to use such special equipment and tools and without stressing or loading the rebar during the connection of the anchor.